1. Field of the Invention
The invention relates to a device for gripping load supports or containers such as palettes, trays or containers of variable dimensions.
2. Description of the Prior Art
In the field of automated storage devices it is well known to use a mobile platform moving in a central alley which allows containers placed in racks on each side of this alley to be automatically removed or stored. This platform comprises for this purpose a device which allows a container to be removed from its storage position, transferred to a work table or replaced in another storage position. The device in question is therefore integral with the platform whose movement it follows. Thus, a device is known which comprises an endless chain with horizontal movement, having a take-up finger and being engaged over four, pinions disposed at the, four apices of a rectangle. The take-up finger engages the container by means of a handle provided for this purpose in its movement parallel to this handle and driving the container in a movement perpendicular to the first one. The container is guided in its movement by two lateral rails which allow it to slide above the chain. Such a device does not allow a container to be moved from one side of the platform to the other. In addition, during the movement of the platform itself along the racks, the container, which must then be immobilized in its drive direction on this platform, is only held by a single finger, and is therefore not immobilized in a very reliable way. Other devices allow the container to be moved from one side to the other of the platform, more especially by the use of two fingers, but the container is again driven by cooperation of a single finger at a time.
This system has been improved by using a flexible element having two fingers which engage successively in the two front and rear handles of the container or receptacle. During storage thereof, the two fingers are disengaged successively from the front and rear handles allowing storage on one side or the other of the platform. For this, a flexible endless element actuated horizontally by several pinions mounted on the platform and driven by a motor is provided with two fingers, one acting by pulling and the other by pushing the receptacle. These fingers occupy an identical position transversely to the longitudinal axis of the flexible element. The advance of the flexible element is such that, in a given position of this advance and after engagement of the pulling finger inside one of the housings, and consecutive driving of the receptacle from a first storage position, this pulling finger momentarily stops driving the receptacle, so as to allow engagement of the pushing finger inside the other housing of the receptacle. The receptacle may then be driven by means of the two fingers. In another given position of the advance of the flexible element, the pushing finger momentarily stops driving the receptacle so as to allow the pulling finger to be disengaged from its housing. Then only the pushing finger alone drives the receptacle to another storage position where it is in its turn disengaged from its housing.
This gripping device finds a particularly interesting application in installations for handling containers or receptacles of standard dimensions, for example when it is a question of storing or handling small parts or documents distributed in a large number of containers of uniform size, this is the case for storing spare parts or else in the field of automatic document search.
There exist however some cases where such storage translators are caused to transfer loads of substantially different nature and dimensions. It happens in fact that in warehouses or stores there is sometimes need to store, in the storage racks on each side of the central alley, not only containers serving as receptacles, but also trays or palettes, carrying packets or loads which may be taken up moreover by other transfer means such as fork-lift trucks.
The known device mentioned, hereinabove which is designed for a well defined type of receptacle; does not allow these loads of varying shapes and dimensions to be gripped.